Boulder
Colorado Springs
, Colorado, United States..jpg)
In geology, a boulder (or rarely bowlder)[1] is a rock fragment with size greater than 25.6 cm (10.1 in) in diameter.[2] Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive.[3] In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks or stones. The word boulder derives from boulder stone, from Middle English bulderston or Swedish bullersten.[4]
In places covered by
the Bronze Horseman in Saint Petersburg
, Russia.
Some noted
rock formations involve giant boulders exposed by erosion, such as the Devil's Marbles in Australia's Northern Territory, the Horeke basalts in New Zealand, where an entire valley contains only boulders, and The Baths on the island of Virgin Gorda in the British Virgin Islands
.
Boulder-sized clasts are found in some sedimentary rocks, such as coarse conglomerate and boulder clay.
See also
- Bouldering, free climbing performed on small rock formations or artificial climbing walls
- Moeraki Boulders, unusually large spherical boulders found in New Zealand
- Monolith, a geological feature consisting of a single massive rock
References
- ^ Webster’s New International Dictionary of the English Language. Springfield, Massachusetts: G. & C. Merriam Company. 1913.
- ISBN 978-0922152896.
- ^ a b "Boulder". Dictionary.com. Retrieved 24 August 2013.
- ^ boulder. (n.d.) Online Etymology Dictionary. Retrieved December 9, 2011, from Dictionary.com website.
External links
Media related to Boulders at Wikimedia Commons
